Research has been actively performed on a wireless power transmission technology that is capable of conveniently supplying power to, or charging, various electronic devices wirelessly. Such a wireless power transmission technology is applied to the wireless charging of a smart phone or an electric car.
With a conventional wireless charging technology of an electronic device, it was possible to wirelessly charge an electronic device by using magnetic induction or magnetic resonance.
A wireless charging method using the magnetic induction refers to a method of supplying power within a short distance using an internal coil of a charger by mounting a coil wound multiple times on a battery cover of an electronic device.
A wireless charging method using the resonance refers to a method of supplying power to an electronic device at a long distance by using the resonance phenomenon of a magnetic field.
A wireless charging method using microwaves refers to a method of transmitting power wirelessly by radiating microwave signals into the air by using an antenna.
However, the magnetic induction charging method of an electronic device is a wireless charging method, in which charging is only enabled within a short distance of several centimeters. The magnetic induction charging method has caused various problems of, for example, mountability since the coil is mounted on the battery cover.
The wireless charging method using the magnetic resonance is advantageous in that charging is automatically performed around a charger, but has a problem in terms of harmfulness to a human body.